The invention concerns a lance holder for oxygen lance tubes with a collet which is adaptable to the diameter of the oxygen lance tube, and of a pressure casing which is arranged on the holder and constructed so as to be slidable longitudinally over the collet with the aid of an adjusting facility, whereby the collet is allocated a deformable sealing casing clamping the lance tube.
Lances with a collet and a pressure casing which is slidable over it serve to hold the lance needing to be refined, and secondly, for example, to assure that the workers operating the lance holder are not in danger when concluding or interrupting the blowing process. Lance holders with a slag run back safety device can be gathered from EP-B1-0 372 098. Here, the pressure casing slides over the collet with the aid of a toggle joint to fix the lance tube. A seal is arranged behind the collet which is squeezed when the collet is slid in order to seal the lance tube tight. Such a lance holder or its collet is in part adapted to various tube diameters, whereby the force necessary for staying leads to the toggle joint often being violently pressed back or struck so that damage to the lance holders occurs. As a consequence, the fixation of the oxygen lance tube is no longer exact. DE-PS-195 47 885 also shows a lance holder allocated to a lance manipulator in connection with which, however, manual labor for staying the oxygen lance tube is largely unnecessary because the pressure casing has available a clamp dog which ensures that an appropriately strong spring then provides for a secure mounting of the lance tube if the clamp dog is released. If a tube end is to be removed and a new oxygen lance tube is to be introduced, compressed air is administered to the clamping piston so that this is pushed against the force of the compression spring. At the same time, the collet is released so that corresponding manipulations become possible. Such a lance holder offers considerable advantages. But the risk of danger to personnel in extreme situations cannot be avoided. Such a threat exists, for example, if the oxygen lance tube is blocked in front, and exists as a rule with slag. When oxygen is delivered, this can then leave the oxygen lance such that a dangerously high pressure builds up in the lance holder and elements associated with it. When the collet is released, a dangerous flying up of the oxygen lance tube or even a springing back of the lance holder occurs.